1. Field of the Invention
The invention relates to a process for the metallurgical treatment of iron metals, especially for producing molten steel. The invention further relates to an associated steelmaking device with at least one metallurgical vessel that can be closed by a swivelling cover, which is connected via a flue gas elbow to a gas purification unit and through the center of which at least one electrode can be run, with a device for filling the vessel with charge material, and with a flush-off opening and a tap opening for hot metal located in the bottom of the vessel.
2. Description of the Prior Art
The marketplace demands better and better quality from the operators of electric steelmaking plants in respect to the level, continuity and price of steel products. In light of fluctuating costs for raw materials, more and more producers are planning to use, in addition to scrap, larger quantities of pig iron (molten or in ingots) in electric steel mills.
Until now, the blowing of pig iron with high oxygen rates was only carried out in converters. For example, a device is known from DE OS 28 03 960 for refining pig iron with oxygen or oxygen-enriched gases, wherein a main hood is provided to collect waste gases that escape during the refining process. The waste gases are suctioned away through an extraction pipe, which is connected to the main hood and leads to a dust removal unit. The extraction pipe has an opening through which an oxygen lance can usually be directed.
The main extraction hood is connected to a cover, which is arranged independently of the metal vessel, and forms with it a unit that can be moved to the side.
Electric arc furnaces are usually operated with direct or alternating current. For example, DE 43 02 285 A1 discloses a double furnace with two furnace vessels (as well as a process to operate this device) that can be covered by covers, which are connected via flue gas elbows to a gas purification unit. FIG. 2 of the aforementioned document shows three electrodes through the cover of a furnace operated with three-phase current and one electrode through the cover and a counterelectrode in the bottom of the vessel of a direct-current furnace. The two furnaces are operated in such a manner that the first furnace is supplied with electric power to melt the charge located in it, while the other furnace remains completely separate from the electric network and is supplied, after charging, with hot flue gases from the first furnace. The metallurgical process used is a one-stage process.
Metallurgical vessels have also been proposed already. For example, DE 34 19 030 C1 discloses a metallurgical reaction vessel, especially a steel works converter, which, for each step of a process and for the operational devices arranged above and/or under the reaction vessel, the corresponding functional component, is installed accessibly in rotary fashion around a vertical rotational axis. The operational devices include an offtake pipe, a charging device, a test lance, a blowing lance and a bottom descent device, for example. These devices are installed in a fixed fashion, while the reaction vessel is rotated into the appropriate position via the vertical rotational axis.
The reaction vessel is suitable, in each instance, for a single process. For example, it is used to produce metal melts, especially steel melts, and to produce gases, e.g., CO gases from coal and a reaction-enhancing substance, which assists the reaction by its presence and is consumed only slightly or not at all, e.g., pig iron melts.